The Cardas Room Setup Guide: FAQ: Room Design

A collection of questions we've received over the years about room design

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Listening Room Slap

Q.) Dear George, Sorry to bother you with my listening room issues. I've always been a fan of your cables. All of my windows are double paned glass. The ceiling is lath and plaster, which is quite fragile. With mirrors and french doors, there are a lot of reflective surfaces. My wife uses a motorized wheelchair in the house. In order to make the living room accessible to her, I have to keep the room open and any rugs to a minimum. The room has a lot of slap and I'm not sure what to do. I could use some help. Best regards, Sam

A.) Hi Sam, Killing slap in an existing room is all about adding soft stuff that looks good to your wife. One of the best choices is Melamine foam. You can get white, paintable, 2 ft. x2 ft. squares that aesthetically, are virtually invisible, but do absolute wonders when it comes to killing slap. If you have trouble finding a local supplier, we sell it here at cardas Audio. Thanks, George

Q.) Hi George, Thanks for the suggestion on the foam. To limit the amount of foam we attach to the ceiling do you have any suggestions on where to locate it? Thanks, Sam

A.) Hi Sam, As far as where to put the foam on the ceiling, make it look right. It should be arranged symmetrically. To reduce the amount of foam used, you can make a simple cross the length and width of the room, with the crossing at the first reflection point. This can be very effective in the listening area. The overall dampening effect is proportional to the amount of foam used. George

Specific Room Resonances

Q.) Thank you! For three years I have been struggling to place my B&W Nautilus 802 speakers and finally came across your website. The speakers are placed on the long wall (zillion dollar view) and I never had ANY soundstage. Out of desperation, I did exactly as you wrote. Magic! I am in a concert hall. Every instrument clear, focused and in place. I am stunned! You cannot believe how happy I am.

I just need one more piece of advice, The glass and hard plaster room is large 26' by 36' with a 13' ceiling and the speakers are 7' away from the front (36') wall and following your formula are 11'4" from the side walls. My chair is 6' from the rear wall. Unfortunately, I have an imbalance of +11 dB at both 100 and 63HZ. Do I move the speakers along the diagonal of the the Golden rectangle to correct for this or do I ignore the diagonal and move them closer or further away from the front wall? I know each room is different but after three years of haphazard moving, just tell me what general steps I should try. Thank you again. - Leonard

A.) Leonard, The room resonances you describe are the direct result of the room dimensions and the fact that the room is so live. The 63Hz is caused by the length. The 100 is caused by both the 13' and the 26' dimensions. This cannot be totaly corrected by moving the speakers, unless you want to give up everything else. You can consider bass trapping, venting the room, modifying the speakers (if there is a port, put a sock in it or a tennis ball or what ever). I hate to suggest EQ, but it does work for this type of thing, if you dont get carried away. Aside from that you can draw a line on the floor from where the speakers now stand to the corner and symetricaly place the speakers on that line. All of the above are compromises of a sort. I would hope that a sock works best. Good luck - George

Q.) Dear George, Thanks again. I totally rearranged my living room and put the speakers on the short wall. I followed your method exactly. (Room size 26’ x 36’ x 13’ high). I should have done this a long time ago. No more booming, no more mushy sound, just the best sound I ever had in my living room. Regards - Leonard

Subwoofer Placement

Q.) Mr. Cardas, with the "Golden Cuboid" theory in mind, I have a two part question on the placement of 2 subwoofers. I want to place both subs outside the left and right main speakers. My room dimentions are 21' wide x 29' deep x 10' high. Where is the optimum placement for the subs?

Also, how high off of the floor should they be, considering room nodes & modes? - Mike

A.) Because the wave length of a subwoofer is so long, compared to room dimensions, subs are traditionaly placed close to the wall-floor junction. In the case of a single sub, it is placed behind the speakers and with stereo subs, outside the speakers. I suggest crossing over at about 40 cycles with your room dimensions, as this will put a null at the multiple of the room length dimension. - George

Which Room?

Q.) Hi George. I am looking at a new home and it has two rooms that could be ideal for my audio/video setup. I would like to get your opinion on which one I should use. The first room is 9' high, 14’8” wide, 16’4” long. The second is 9’ high, 10’10” wide, and 20’5” long. Thanks - Rick

A.) Hi Rick. The 9' x 14' 8" x 16'4" would be my choice. Carpet with thick pad, a little softening of the walls and this should be a great room. The 9' x 10' x 20' would have very strong nodes because of the 10 x 20 multiple. - George